The airborne multi-wavelength water vapor differential absorption lidar WALES: system design and performance

A high-performance airborne water vapor differential absorption lidar has been developed during the past years. This system uses a four-wavelength/three-absorption line measurement scheme in the 935 nm H₂O absorption band to cover the whole troposphere and lower stratosphere simultaneously. Additional high spectral resolution aerosol and depolarization channels allow precise aerosol characterization. This system is intended to demonstrate a future space-borne instrument. For the first time, it realizes an output power of up to 12 W at a high wall-plug efficiency using diode-pumped solid-state lasers and nonlinear conversion techniques. Special attention was given to a rugged optical layout. This paper describes the system layout and technical realization. Key performance parameters are given for the different subsystems.     

Electromagnetic transition strengths and nuclear moments in123Xe

The level structure of¹²³Xe has been studied with the¹¹⁴Cd (¹²C, 3n) and^?Cd (¹³C, 4n) reactions using in-beamγ-ray spectroscopy. The yrast cascade on the low lying odd parity states originating from theh _11/2 neutron orbital has been investigated yielding lifetimesτ of 18(3) ps, 2.2 (4) ns and 17(2) ns for the 15/2^?, 11/2^? and 9/2^? states, respectively. Theg-factor of thet _1/2=5.2 μs isomer has been measured to beg=?0.256(2). From the time differential observation of the electric quadrupole interaction in a¹¹⁴Cd single crystal the spin of this isomer has been determined to be 7/2 and from the coupling constante ² Qq/h=116(2) MHz the quadrupole moment was deduced. The results are discussed in the framework of the triaxial rotor plus particle model.     

Quadrupole moment of the 19/2− isomer in115Sb

The quadrupole moment of the 19/2^? isomeric state in¹¹⁵Sb has been measured using the time differential perturbed angular distribution method. From the quadrupole coupling constante ² Qq/h=66(3) MHz atT=370 K in a Bi host the moment ratio is obtained relative to the stable ground state of¹²¹Sb as ¦Q(¹¹⁵Sb, 19/2^?)/Q(¹²¹Sb, 5/2⁺)¦ =1.45(7) resulting in a moment of ¦Q(¹¹⁵Sb, 19/2^?)¦=52(6) fm².     

The g-factor and the electric quadrupole moment of the 7/2+ isomer in125Xe

The time differential perturbed angular distribution method (PAD) was used to measure theg-factor and the electric quadrupole interaction in a Cd single crystal for thet _1/2=140 ns,I ^π=7/2⁺ isomer in¹²⁵Xe. Theg-factor isg=+0.264(10) and the quadrupole coupling constante ² Qq/h=122.1 (6) MHz at 552 K. The lifetime of theI ^π=11/2⁺ state was measured to beτ=11.3 (1.1) ps by the recoil distance method (RDM). From an analysis of the spectroscopic data using the triaxial-rotor-plus-particle (TRPP) model the quadrupole moment of the 7/2⁺ isomer is deduced to beQ=1.40 (15) b yielding an electric field gradient (efg)eq=3.6(4)·10¹⁷ V/cm² for XeCd.     

Temperature dependence of the quadrupole interaction of67Ge and67Zn ins-p metals

The temperature dependence of the electric quadrupole interaction was measured on the 9/2⁺ isomeric state of⁶⁷Ge in metallic Zn, Cd, In, and Sn and on the 9/2⁺ isomeric state of⁶⁷Zn in Cd metal. For all investigated systems, the temperature dependence reproduces very well aT ^1.5-relation. The analysis shows that the strength of the temperature dependence in the pure metals is correlated to 1/(M _D ² ) ( _D =Debye-temperature). This favours lattice vibrations as the main component of the temperature dependence of the electric field gradient. The strength of the temperature dependence measured on an impurity atom generally differs from the value of the pure host. Possible explanations for this effect are discussed.     

Nuclear probes in the materials science of solar cells

We present background material about solar cells and the copper-indium-sulphur system and then discuss three important processes for the production of CuInS₂ solar-cell material. These include: sulphurization of metallic copper-indium precursors, physical vapour deposition of the elements, and three-source molecular beam deposition. Using perturbed angular correlations with the¹¹¹In-¹¹¹Cd probe, we are able to identify the indium-containing phases of the system and thus to characterize the cited production processes. The prospects of nuclear probe methods in the development of solar-cell materials are discussed.     

Nuclear structure study of the neutron deficient cadmium isotopes100, 101, 102Cd

The neutron-deficient nuclei^100,101Cd were identified for the first time in — beam following the reactions⁵⁸Ni +^46,48Ti and⁵⁸Ni +⁵⁰Cr at 230 MeV and 245 MeV bombarding energy of the⁵⁸Ni beams. The-decay of the isotopes^100,101,102Cd was studied inp, pp,n, nn, andn prompt and delayed coincidence spectra. Isomers were found with spin and half life {ie1-01}=8⁺, T_1/2=52(5) ns in¹⁰⁰Cd, {ie1-02}=(19/2⁺), T_1/2=4.6(4) ns in¹⁰¹Cd and {ie1-03}=8⁺, T_1/2=56(4) ns in¹⁰²Cd. In a PAD experiment theg-factor of the {ie1-04}=8⁺ isomer in¹⁰⁰Cd was measured to be g=1.24(6). Using the reaction³⁶Ar +⁷⁰Ge at 135 MeV energy of the³⁶Ar beam, theg-factor and the quadrupole moment of the {ie1-05}=8⁺ isomer in¹⁰²Cd were measured to be g=1.29(3) and Q=87(10) fm², respectively. The spectroscopic results are discussed within a shell model approach using a¹⁰⁰Sn core, which accounts well for the electromagnetic properties of the proton aligned isomers. The structure of the spherical neutron states, dominated by the close lying vd_5/2, g_7/2 orbitals, and the gradually developing quadrupole collectivity are reproduced by the shell model calculations.The authors gratefully acknowledge fruitful discussions with K. Heyde and are indebted to him for communicating unpublished theoretical results. The help of N.A.F.M. Poppelier and A.G.M. van Hees in running the RITSSCHIL code is very much appreciated.     

The Suprising Variety of Products from Reactions of P-P Bonds with Dichlorogermylene

Abstract

Insertion of dichlorogermylene (from GcCl₂-dioxane) into the P-P bonds of tetraalkyldiphosphanes ((PRR)₂ (2a: R, R ? i-Pr; 2b: R? t-Bu, R?i-Pr; 2C; R, R, ?t-Bu) leads 10 dichlorobis(dialkylphosphanyl)germanes 3a-c. With 2a. the insertion remains incomplete: 38 exists in an equilibrium with an adduct of diphosphane 2a with GeCI₂, Subsequently 3b and 3c undergo a-climinarions to dialkylchlorophosphanes Sb and Sc and the dimeric phosphanylgermylenes (RR PGeGl)² 4b and 4c [1]. Similar to the above (but in absence of dioxane), reacting the richlorogcrmylphosphane i-Pr(t-Bu)PGeCL₃, 7c [2] with the related trichlorosilylphosphanc i-Pr(t-Bu)PSiCl₃ provided a mixture of SiCl₄, 1c, 3c, 5c and 7c, 3a and 3c have been trapped as inert molybdenum complexes (CO)₄ MO(μ-PRR)₂ GeGl₂ 6a and 6c from cquilibrilia conraining la/ 2a/ 3a and 3c/ 4c / 5c / 7c respectively.     

The Knight shift of francium in mercury

For Fr in Hg an extremely small Knight shift has been found as compared to the shift known for an alkali metal host. It indicates an almost complete loss of the outer s-electron of the alkali atom Fr when embedded in liquid mercury. This may be understood as a consequence of the small ionization energy of the Fr atom in comparison with the large work function of mercury.